cstage zero-filled the payload; mirror the landed wwstage emission. Flips the residual row to cs==ww==correct. Task #43.
Widening a global struct into a tagged slot copied word0 only; copy the full payload from g(SB). Both-wrong pair: cstage zero-fills the payload (filed task #43); rows pin ww-runtime-correct with the documented cstage residual. Review item #50.